Insulating support for heating elements



March 30, 1954 P. F. MEVTZ INSULATING SUPPORT FOR HEATING ELEMENTS Filed April 18, 1950 INVEN TOR. PAUL F. METZ ATTORNEY Patented Mar. 30, 1954 INSULATING SUPPORT FOR HEATING ELEMENTS Paul Francis Metz, Hamilton, Ohio, assignor to Avco Manufacturing Corporation, Cincinnati, 0hio,.a.corporation of Delaware ApplicationApril 18; 1950, Serial No. 156,569

5 Claims.- (Cl. 174138) 1 ,The'present invention relates to an? insulating support'for an electric heating element andhas; particular reference to a ceramic insulating. sup port. used to position an electric heating. elementwithin an electric range.

It is common practice today among manufacturers of electric ranges to fabricate heating. units for inclusion in the oven and broiler spaces of an electric range as removable components. Such a unit may take theform of a flat base plate to which is secured a plurality of ceramic insulating. supports by which a. helical resistance type: heating coil is positionedin a predetermined pat tern spaced: from theb'ase plate. Thus, broadly speaking, structures of. this type are well known in the range art and a wide variety of ceramic supportshasbeen used in such installations with a degree of success. v

A well known type of support which is widely usedconsists simply of a ceramic hook having an enlarged base which engages the marginsof a complementary opening formed in theanchor' plate. Such supports can only be keptin positionrelative to the: anchor plate by the tension forces exerted on the supports by the heating. elements assembled therewith. In other words, the. heating element draws the enlarged base of: the support against the margins of the hole through which themain body of thesup'porthas been passed. This. particular type of support has many shortcomings, since no provision is made to assure anygparticulor orientation. with its anchor plate. Furthermore, the supports may be dislodged from the anchor plate should the tension of the heating element vary, which. is often the case; In addition, the, anchor plate: can not be handled with the supports in place prior to the time that the heating element is installed.

Anothercommon type-of. heating element sup port that. obviates many of the difiicultiesof the foregoing: type consists of. a ceramic grommet which is secured totheanchor plate by metal clips or engaging: arms. Ceramic grommets when thus assembled to the anchor plate: permit handlingof thev partially completed heating unit. prior to the installation of the: heating element. However, the. heating elementxisinstalled byxbein'g strungthrough. the plurality of grommets to form the" desired. heating. element. pattern. Should one of these grommets break or be defective: in" any way it is necessary: to unstrin'g: theheating: element to the point where the broken. grommet may be. disengaged from the element and-replacedby -a: new grommet; This: is: a

serious difiiculty' since the supports, being made Still another type of prior. art support.- is: a-

ceremic hook having anenlarged base-inwhich is formed a small notch for engaging the mar. gin at one side or" a complementary opening-.provided inthe anchorplate for: receiving the support. This type. is an improvementv over the foregoing prior art type although it also has.

shortcomings, beingv dependent upon the heating element proper in order to maintain its err-1 gagement with the anchor plate. Furthermore,. the possibility of assemblingth'e. supports to the anchor. plate in a variety of positions often leads to confusion.

An important object of the present invention is the provision of a ceramic heating element support. which may be assembled: in only one posi-- tion to its base or anchor plate thereby preclud Not-only does the present invention preclude improper. .orientation relative to one face ofthe anchor plate'but it also prevents assembly of the support. on the wrongside of: the anchor plate;- It will;

ing. incorrect assembly with the plate.

be appreciated that this has particular value in mass production operations involving relatively unskilled labor which must-be employedt'o pro duce ranges at. competitive prices.

Another object of the present invention: is to provide an insulating support which innormal use-is firmly secured'to itsanchor plate but'which: may beremovedtherefrom should any necessity therefor arise. tageof a heating unit incorporating. supports 0fthe type disclosed is that asi'ng-le insulating. support of the plurality secured to: the anchor plate may be replaced without disturbing. the heating: element. proper. The importance: of this ad vantage will be appreciated when. it is pointedout. that heating. elements are very; brittle: after use and difficult to 'handlewithout fracture.

It alsov arr object of the inventiomto provide a-heating'element" support which, for satisfactory installationwith the anchor plate, is totallyin'dependent ofany tension forcesthat may be: exerted by' the heating element when-assembled on the supports. The importance of this-oldiect will It is noteworthy" that an advan be readily understood by those skilled in the art sinc it is well known that the tension of a heating element varies considerably as its temperature varies during use.

A still further advantage of the invention is that it makes possible the assembly of a plurality of heating element supports firmly to an anchor plate without the installation of the heating element proper. Thus, a partially completed heating unit, comprising merely the insulating sup ports secured to the anchor plate, may be handled without danger of the supports becoming disengaged from the plate. This feature or the invention facilitates handling and storing of partially completed components which is an aid in mass production methods.

The herein disclosed invention avoids all of the shortcomings of the prior art devices and represents a material advance in the heating unit field. The novel features that are considered characteristic of the invention are set forth in the appended claims; the invention itself, however, with additional objects and advantages thereof will best be understood from the following descrip tion of a specific embodiment when read in conjunction with the accompanying drawings, in-

which:

Fig. 1 is a side elevational view drawn to an enlarged scale showing an improved heating element support made according to the teachings of the present invention;

Fig. 2 is a top plan view of an opening formed in an anchor plate in preparation for the installation of a support;

Fig. 3 is a cross-sectional view taken on plane 3-3 of Fig. 2 showing in cross-section an outstanding anchor tab for securing the support to the anchor plate and also showing inelevation a locating ear which insures proper installation of the support;

Fig. 4 is a sectional view taken along plane 4-4 of Fig. 2 showing a position Whichthe support assumes in the course of its assembly to the anchor plate;

Fig. 5 is a view taken on plane 55 of Fig. 6 showing the support in engagement with the cating ear, plane 5-5 also being indicated in Fig. 2 to show its orientation to the opening provided in the anchor plate; and

Fig. 6 shows the position of the support relative r to the anchor plate prior to and after the anchor tab is bent from its outstanding position into the plane of the anchor plate.

As shown particularly well in Figs. 1 and 5 the insulating support, generally designated 1, is secured in depending relation to an anchor plate, generally designated 2. Although only one support is shown in the drawings, it should be understood that a plurality may be provided in a predetermined pattern on the anchor plate to define the desired configuration of a conventional resistance type heating element which may take the form of a helical, coiled resistance wire (not shown). The heating element is supported by a hook 3 which forms a coil-receiving throat The throat of the support is usually made slightly larger than the outside diameter of the heating element coils although if desired, it may be made considerably larger than the coils.

It will be obvious to those skilled in the art that, although the supports are described to be dependng from the anchor plate, it would be relatively simple to construct a heating unit having the heating element disposed above the anchor plate.

As indicated in Fig. 6, the support is relatively narrow having two parallel side faces 5 and 6, the side faces terminating at a fiat base I (see Fig. l). A slot 8 is provided near base 1 on the side of the heating element support in common with the opening of the coil-receiving throat. A rectangular open recess 9 is provided at "the other side of the support and has a face 9a which lies in a common plane with face Ba of slot 8 for a purpose to be described more fully hereinafter. The width of the slot, which is considerably less v than that of the recess, is slightly greater than the thickness of anchor plate 2 to which the support is to be assembled.

The slot and recess define a region of decreased width, or a root section II), adjacent the base 1. This root section is surrounded closely on all sides by the anchor plate when the support is in assembled relationship therewith.

An irregular opening, generally designated ll, of generally rectangular shape is provided in anchor plate 2 to receive the insulating support. This opening includes a rectangular extension l2 and is bounded in part by an anchor tab l3, which is formed from material projecting into the opening and which is struck out of the plane of the anchor plate in preparation for the insertion of the support. An up-turned locating ear I4 is also provided at the side of the opening ll opposite rectangular extension I2 and, as shown in Fig. 3, is disposed on the same side of the anchor plate as anchor tab l3. Re-entrant corners [5 of opening II are provided to minimize stress concen-- trations within the anchor plate that would otherwise be favored if sharp corners were present.

In order to assemble a support to the anchor plate, it is first located so that the flat base 1 forms an acute angle with the plane of the anchor plate as shown in Fig. 4. When the support is in this position, parallel faces 5 and 6 are normal to the plane of the anchor plate and recess 9 is engaged with edge 16 of opening ll while corner I! of the support is positioned within extension l2.

After the support is positioned as shown in Fig. 4, it is subjected to a pure rotation until slot 8 is in position to engage the anchor plate and recess 9 is in position to engage upturned locating ear [4. Thereafter the support is subjected to a pure translation in a direction normal to its side faces and is moved from the phantom line position to the full line position shown in Fig. At the end of this movement slot 8 of the support is engaged with margin ill of opening II and recess 9 is engaged with ear I4 with faces 8a and 9a resting on the upper face of the anchor plate.

Assembly of the support to the anchor plate is completed when anchor tab i3 is bent from the phantom line position to the full line position shown in Fig. 6. This displacement of the anchor tab firmly secures the support at the plane of its root section to the anchor plate in a particular depending relationship therewith. Should it be necessary for any reason to remove or replace the support, this may be done merely by bending the anchor tab out of the plane of the anchor plate and reversing the steps which have been outlined in describing the mode of assembly.

It should be noted that when assembled to the anchor plate, the support has a particular orientation therewith, not only being disposed on a certain side of the plate but also having a certain position relative to that side which is deter-,v

mined by the formation of opening it and locating ear is in the plate. It will be readily apparent from the drawing that the support must be placed on a certain side of the anchor plate be cause, when in assembled relationship therewith, coplanar faces 8a and 90!. must embrace a common plane face of the anchor plate. Furthermore, although the support is positioned on the right side of the anchor plate, it cannot be rotated and inserted backwards in its receiving opening because ear 14 must be engaged by recess 9, the ear being much too large to fit within slot 8.

Since improper orientation of the support relative to the anchor plate is precluded, it will be understood that the use of the present invention aids in eliminating errors in the assembly of heating units for electric ranges or similar devices. It will also be obvious from the foregoing that the supports are firmly secured in the anchor plate after the anchor tabs are bent into the plane of the plate. The locked engagement of the supports makes possible the handling of the assembly regardless of whether or not the heating element is engaged in the hooks of the supports, since engagement of the supports with the anchor plate is totally independent of any force exerted by the heating element coils.

The insulating supports may be formed from any suitable refractory material such as commonly used for electrical insulators. The anchor plate may be made from a wide variety of materials but preferably is formed from a piece of soft, low-carbon steel to facilitate the bending of tab 13 and ear 14. Protective surface treatments may be applied to the anchor plate, if desired.

Whereas the present invention has been described with particular reference to electric ranges, it should be understood that it may be applied with equal utility and advantage to any structure in which an electric heating element must be supported adjacent a support member.

Having described a preferred embodiment of my invention, I claim:

1. A heating unit component for use in mounting a helical coil heating element within an electric range or the like, comprising an insulating support formed to define an open throat for receiving the heatin element, said support having remote from the throat a base portion adjacent which is formed a slot and opposite the slot an enlarged recess defining a root section of said support therebetween, an anchor plate formed to define a support-receiving opening, said opening having a portion of sufiicient width to permit the I passage of the base of said support therethrough when the recess is engaged with said anchor plate adjacent one edge of the opening, the opening also including a section adjacent to but smaller than the first portion and slightly larger than the root of said support, said section having adjacent one side thereof a locating ear stuck out of the plane of the anchor plate for engagement with the recess, said root being positioned within the section when said support is assembled with said anchor plate with the ear in engagement with the recess, an anchor tab formed integrally with said anchor plate adjacent the first portion of the opening for securing said support to said anchor plate when disposed in a common plane therewith in position obstructing the first portion of the opening.

2. In a heating unit a. ceramic insulating support, an anchor plate formed to define an opening for receiving said support, a locating ear formed integrally with said anchor plate adjacent the opening, said support being formed to define a slot for assembled engagement with the edge of the opening and a recess for assembled engagement with the locating ear, and an anchor tab formed integrally with said anchor plate for securing said support within the opening when said anchor tab is disposed within the plane of said anchor plate.

3. In a heating unit, a ceramic insulating support, an anchor plate formed to define an opening for receiving said support, means formed integrally with said anchor plate for locating said support relative to said plate by engagement with a complementary recess formed in said support, and means formed integrally with said anchor plate to lock said support within the anchor plate opening when the second named means is disposed in the plane of said anchor plate.

4. In a heating unit, an insulating support including a base section, a plate formed to define an opening for receiving said base section, said plate having a projection adjacent the openin therein, said base section being formed to define a recess in a side face thereof for cooperative engagement with said projection, said opening being larger than said base section adjacent the recess whereby said support may be inserted through said opening and shifted in a direction parallel to the face of said plate until the recess is in engagement with said projection, and bendable means formed integrally with said plate for partially blocking said opening and preventing movement of said support relative to said plate after said support has been shifted into engagemen with said projection.

5. In a heating unit, an insulating support including a base section, a plate formed to define an opening for receiving said base section, said base section being formed to define a recess for cooperative engagement with said plate adjacent the opening, said opening being larger than said base section adjacent the recess whereby said support may be inserted through said opening and shifted in a direction parallel to the face of said plate until the recess is in engagement with said plate, and bendable means integrally formed with said plate for partially blocking said opening and preventing movement of said support relative to said plate after said support has been shifted into engagement with said plate.

PAUL FRANCIS METZ.

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